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Pixels

October 28th, 2010 Andrei

To understand the term of digital sensors we have to imagine an array of buckets collecting rain water. Digital sensors work the same way buy they consist of an array of pixels collecting photons, the minute energy packets of which light consists. The light sensitive photodiode converts the number of photons collected in each pixel into an electrical charge. For a camera to be able to process the values into the final digital photography, the electrical charge is converted into a voltage, amplified and then converted again to a digital value, using analogue to digital converter. Digital compact cameras have substantially smaller sensors then a digital SLR, although they might have a similar pixel count. This fact determinants a change in the pixel size (smaller for digital compact cameras), the resulting photography having a lower quality.

To understand better, we have to compare a digital photography with a spreadsheet with rows and columns which stores the pixel values generated by the sensors. Pixels in a digital photography have no size until they are displayed on a monitor or printed. For instance, on a 4″ x 6″ print, each pixel in a 5 megapixel image would only measure 0.01mm, while on an 8″ x 10″ print, it will measure 0.05mm.